Characterization of a “Water-soaked Brown Flesh” Disorder in Peach Fruit

Abstract

This study characterized the “watercore-like” disorder in which the flesh of mature fruit in peach (Prunus persica Batsch) exhibits a water-soaked brown discoloration. There were varietal differences in the incidence of the disorder with ‘Kawanakajima Hakuto,’ ‘Beni Shimizu’ and ‘Hana Shimizu’ exhibiting higher rates. The incidence of disorder in ‘Hana Shimizu’ fruit ranged from 23 to 54% over the three years. In all cultivars, the disorder was highest on the side opposite to the fruit suture, then both cheeks and the suture, in that order. Fruit with the disorder showed higher weight, and total sugar, sucrose, sorbitol, water soluble pectic substances and total phenolic contents but lower flesh firmness, total amino acid concentrations and hydrochloric acid soluble pectic substances compared to normal fruit. The highest concentration of total soluble solids was observed at the portion of both cheeks of the fruit, followed by the opposite side of the suture and the suture. Symptoms of the disorder were prominent in mature fruit. We propose that “water-soaked brown flesh” be considered a common term for this disorder based on the fact that the symptoms of “watercore-like” disorder as it is commonly known in Okayama were similar to those of “watercore” or “internal browning” disorder, which is the popular term used in other peach producing areas in Japan.